/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.wsinfra.wse.matching;

import java.util.Calendar;
import java.util.Enumeration;

/**
    This thread cycles through the list of subscriptions and checks to see
    if any of the sucsbriptions have expired.

    @author Shrideep Pallickara
    $Date: 2005/07/29 22:41:30 $
    $Revision: 1.4 $
*/


public class ExpiryDetectionThread extends Thread {
  private long SLEEP_INTERVAL = 100;
  private boolean keepRunning = true;
  private SubscriptionManagement subscriptionManagement;
  private SubscriptionExpiryListener expiryListener;

  private String moduleName = "ExpiryDetectionThread: ";

  public ExpiryDetectionThread(SubscriptionManagement subscriptionManagement,
			       SubscriptionExpiryListener expiryListener) {
    this.subscriptionManagement = subscriptionManagement;
    this.expiryListener = expiryListener;
  }


  /** Sets the interval at which this thread should perform checks */
  public void setCheckingInterval(int sleepInterval) {
    if (sleepInterval > 20) {
      SLEEP_INTERVAL = sleepInterval;
    } else {
      System.out.println(moduleName + "Rejected attempt to check every [" +
			 sleepInterval + "]. Specify a larger value.");
    }
  }

  public void terminateThread() {
    keepRunning = false;
  }

  public void run() {
    while (keepRunning) {
      try {
	sleep(SLEEP_INTERVAL);
	cycleThroughSubscriptions();


      } catch (InterruptedException e) {
	System.out.println(moduleName + "Problems sleeping " + e);
	break;
      }

    }// end while
    System.out.println(moduleName + "Has stopped running.");
  }//end run()


  public void cycleThroughSubscriptions() {
    Enumeration identifiers =
      subscriptionManagement.getSubscriptionIdentifiers();
    Calendar currentTime = Calendar.getInstance();

    while (identifiers.hasMoreElements()) {
      String identifier = (String) identifiers.nextElement();
      SubscriptionEntry subEntry = subscriptionManagement.getEntry(identifier);
      if (subEntry == null) {
	continue;
      }

      if (subEntry.isExpired(currentTime)) {
	notifyExpiration(subEntry);
      }

    }// end while
  }


  /** Notify the registered listener regarding the subscription's expiry. */
  private void notifyExpiration(SubscriptionEntry expiredEntry) {
    if (expiryListener != null) {
      expiryListener.onSubscriptionExpiry(expiredEntry);
    } else {
      System.out.println(moduleName + "The registered listener for " +
			 "subscription expirations is NULL!");
    }
  }


}
